1. Field
The present disclosure relates to genetically engineered yeast cells capable of producing lactate, methods of producing the yeast cells, and methods of producing lactate by using the yeast cells.
2. Description of the Related Art
Lactate is an organic acid that is widely used in a variety of industrial fields, including the food, pharmaceutical, chemical, and electronic industries. Lactate is a colorless, odorless, water-soluble, low-volatile material. Lactate is not toxic to the human body, and thus is used as a flavoring agent, a souring agent, a preserving agent, or the like. Lactate is also used as a source of polylactic acid (PLA) that is an environmentally friendly, biodegradable plastic known as an alternate polymeric material. PLA is a polyester-based resin prepared for polymerization by conversion of lactic acid to its dimmer, i.e., lactide, and then, by ring-opening polymerization of the lactide. In this regard, PLA may be processed into a variety of forms, such as films, sheets, fibers, and injections. Accordingly, PLA has been increasingly demanded as a bioplastic material to replace the existing general-purpose petrochemical plastics, such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polystylene (PS). In addition, lactate has both a hydroxyl group and a carboxyl group, and thus has desirable reactivity. Accordingly, lactate is easily converted to industrially important compounds, such as lactate ester, acetaldehyde, or propylene glycol, and thus, in the chemical industry field, PLA also has attracted attention as a next-generation alternative chemical raw material.
In recent years, lactate is industrially produced by a petrochemical synthesis process and a biotechnological fermentation process. According to the petrochemical synthesis process, ethylene derived from crude is oxidized, and via acetaldehyde, lactonitrile is obtained by addition of hydrogen cyanide. Then, lactonitrile is purified by distillation and hydrolyzed by using hydrochloric acid or sulfuric acid, thereby producing lactate. According to the biotechnological fermentation process, renewable carbohydrates, such as starch, sucrose, maltose, glucose, fructose, and xylose, are used as substrates to produce lactate. Thus, in view of the art a strain capable of producing lactate in an effective manner and a method of producing lactate using said strain have been demanded. In order to meet these needs, a method of producing lactate by using a microorganism has been recently developed. However, when using a microorganism, due to its homeostasis, mass production of only one material is restricted, and thus, the present inventive concept is completed in the process of studying solutions for the problem.